JP3489647B2 - Vehicle height adjustment device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle, in particular, a vehicle having a low vehicle height in order to improve the ease of getting on and off, and a high vehicle height when traveling on a bad road such as a railroad crossing or a steep slope. The present invention relates to a vehicle height adjusting device suitable for a fixed route bus.

[0002]

2. Description of the Related Art Conventionally, one end of a leaf spring attached to a front axle of a four-wheel drive vehicle is attached to a chassis frame via a front spring bracket, and the other end of the leaf spring is attached to a crank arm via a shackle. It is pivotally attached to one arm, and the approximate center of this crank arm is pivotally attached to the chassis frame via a bracket.
Further, there is disclosed a leaf spring type suspension with a vehicle height adjusting function in which the other arm of the crank arm is pivotally attached to a piston rod of a hydraulic cylinder fixed to a chassis frame (JP-A-7-251622). In this leaf spring type suspension, a hydraulic pump is connected to the hydraulic cylinder via a hydraulic switching valve, and the hydraulic switching valve is configured to be switched by a vehicle height switching switch provided in a driver's seat.

In this leaf spring type suspension, when the vehicle height changeover switch is turned on during traveling on a rough road, the hydraulic pressure changeover valve is changed over to supply the pressure oil from the hydraulic pump to the hydraulic cylinder. The supply of pressure oil to the hydraulic cylinder causes the piston rod to project, and one arm of the crank arm pushes down the other end of the leaf spring via the shackle, increasing the vertical spacing between the axle and the chassis frame, and increasing the chassis frame. The height of the ground is high.
As a result, the running performance on a rough road is improved.

[0004]

However, in the above-mentioned conventional leaf spring type suspension with a vehicle height adjusting function,
Since the vehicle height is adjusted by moving the other end of the leaf spring up and down, there is a problem that the vehicle height can be adjusted only about half the vertical movement distance of the other end of the leaf spring.
If one of the crank arms is lengthened to eliminate this point, when the vehicle height is increased, the leaf spring inclines backward and downward at a relatively large angle, which may impair the original function of the leaf spring. there were. Further, in the above-mentioned conventional leaf spring type suspension with vehicle height adjusting function, a hydraulic pump has to be newly mounted, which causes a problem of increasing the number of parts and the number of assembling steps. An object of the present invention is to keep the vehicle height low during normal running, and to quickly raise the vehicle height by a simple operation when necessary, and to increase the leaf count with a slight increase in the number of parts and assembly work. It is an object of the present invention to provide a vehicle height adjusting device for a vehicle that can efficiently adjust the vehicle height without impairing the function of the spring.

[0005]

The invention according to claim 1 is
As shown in FIGS. 1 and 3, a leaf spring 13 that is interposed between the axle 11 and the chassis frame 12 to suspend the chassis frame 12, and the axle 11 and the chassis frame 12 are provided.
This is an improvement of a vehicle including a shock absorber 14 interposed between the shock absorber 14 and the leaf spring 12 for suppressing vibration of the leaf spring 12.
The characteristic structure is that the shock absorber 14 has an outer cylinder 1 whose one end is pivotally attached to the chassis frame 12 or the axle 11.
7, one end of which is pivotally attached to the axle 11 or the chassis frame 12 and the other end of which is slidably inserted into the outer cylinder 17 and is internally
The inner cylinder 19 in which the liquid 26 is sealed, the first piston 21 slidably inserted in the outer cylinder 17, the second piston 22 slidably inserted in the inner cylinder 19, the first piston 21, and The second piston 22 is connected and the insertion hole 23a is provided along the axis.
A liquid supply / drainage means 24 capable of supplying / discharging the second liquid 29 to / from a piston rod 23 in which a second liquid 29 is formed and a first liquid chamber 31 formed between the inner end surface of the outer cylinder 17 and the top surface of the first piston 21. When,
A second piston 22 formed in the inner cylinder 19 and divided by the second piston 22 into one end side and the other end side of the inner cylinder 19, respectively.
And the third liquid chambers 32 and 33, an orifice 23b formed on the side surface of the piston rod 23 adjacent to the second piston 22, and communicating the second and third liquid chambers 32 and 33, and the top surface of the first piston 21. By sliding the valve body 34 slidably inserted in the recess 21a formed in the recess 21a and the sliding of the valve body 34 integrally formed with the valve body 34 in the recess 21a, the slide hole 23a is slid. The valve body rod 36 that can open and close the orifice 23b is interposed between the valve body 34 and the bottom surface of the recess 21a, and urges the valve body 34 in a direction away from the bottom surface of the recess 21a and is supplied to the first liquid chamber 31. A vehicle height changeover switch 51 is provided in the driver's seat, which has an elastic body 41 having an elastic force smaller than the pushing down force of the valve body 34 due to the pressure of the second liquid 29. , Turn off the vehicle height switch 51 There is to configured to supply and discharge the second liquid 29 into the first liquid chamber 31 via the liquid supply and discharge means 24 by obtaining.

In the vehicle height adjusting device according to the first aspect of the present invention, the vehicle is normally in a state where the first piston 21 of the shock absorber 14 is in contact with the inner end surface of the outer cylinder 17, that is, the vehicle height is lowered. Since the vehicle runs on a flat paved road, it is easy to get on and off the vehicle. Further, at this time, since the orifice 23b is opened, the passage of the first liquid 26 in the inner cylinder 19 through the small orifice 23b becomes a resistance of the vertical movement of the second piston 22 relative to the inner cylinder 19, Vibration of the leaf spring 13 can be suppressed. When the vehicle travels on a rough road, the liquid supply / drainage means 24 is set to the second position by switching the vehicle height changeover switch 51.
The liquid 29 is supplied to the first liquid chamber 31. The second liquid 29 supplied to the first liquid chamber 31 pushes down the valve body rod 36 via the valve body 34 against the elastic force of the elastic body 41 to close the orifice 23b, and further the first piston Since 21 is lowered with respect to the outer cylinder 17, the vehicle height becomes high, and the vehicle can smoothly travel on a rough road.

The invention according to claim 2 is the invention according to claim 1, further, as shown in FIG. 1, the second liquid 29 supplied to and discharged from the first liquid chamber 31 is oil, and Supply and discharge means 24
Has a hydraulic pump 37 for supplying / discharging the second liquid 29 to / from the power steering gear, a switching valve 39 provided in a pipe line 38 connecting the hydraulic pump 37 and the first liquid chamber 31, and a vehicle height switching switch 51. By switching the switching valve 39 to supply and discharge the second liquid 29 to and from the first liquid chamber 31. In the vehicle height adjusting device according to the second aspect, since the existing hydraulic pump 37 for power steering can be used as the liquid supply / discharge means 24, the number of parts and the number of assembling steps can be slightly increased.

The invention according to claim 3 is the invention according to claim 1 or 2, further, as shown in FIG. 4, when the first piston 81 comes into contact with the inner end surface of the outer cylinder 17, First piston fixing means 71 for fixing the piston 81 to the outer cylinder 17.
And first piston position sensors 91a and 91b for detecting the position of the first piston 81, and the first piston sensor 91.
a, 91b and a controller 78 for controlling the first piston fixing means 71 based on the respective detection outputs of the vehicle height changeover switch 51. In the vehicle height adjusting device according to the third aspect, the first piston position sensor 9
When the controller 1a detects that the first piston 81 has come into contact with the inner end surface of the outer cylinder 17, the controller 78 determines that the sensor 91
The first piston fixing means 71 is operated based on the detection output of a to fix the first piston 81 to the outer cylinder 17.

The invention according to claim 4 relates to claims 1 to 3.
The invention according to claim 1, further comprising:
The accumulator 28 is connected to the first liquid chamber 31. In the vehicle height adjusting device for a vehicle according to claim 4, the accumulator 28 can be used even when the vehicle height is increased.
By repeating compression and expansion of the gas 30 therein, the first piston 21 or 81 moves relative to the outer cylinder 17.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a first embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIGS. 1 to 3, a leaf spring 13 that suspends the chassis frame 12 is interposed between the axle 11 of the front wheels of the route bus and the side member 12a of the chassis frame 12, and the axle 11 and the side member 12a. A shock absorber 14 for suppressing the vibration of the leaf spring 13 is interposed between and. The shock absorber 14 has an outer cylinder 17 whose upper end is pivotally attached to the side member 12a via a shaft 16, and a lower end is pivotally attached to the axle 11 via a shaft 18, and an oil 26 which is a first liquid is enclosed therein. The inner cylinder 19, the first piston 21 slidably inserted in the outer cylinder 17, the second piston 22 slidably inserted in the inner cylinder 19, and the first and second pistons 21 and 22 are connected. Piston rod 23 and outer cylinder 1
Oil 29, which is the second liquid, in the first liquid chamber 31 formed in
And a liquid supplying / discharging means 24 capable of supplying and discharging.

The outer cylinder 17 is formed in a cylindrical shape whose upper end is closed by the upper wall 17a and its lower end is opened, and the inner cylinder 19 is formed in a cylindrical shape whose both ends are closed by the upper wall 19a and the lower wall 19b ( 1 and 2). The upper end of the inner cylinder 19 is the outer cylinder 1.
7 is slidably inserted from the lower end thereof, and a small amount of gas 27 such as nitrogen gas is enclosed in the inner cylinder 19 in addition to the oil 26. In the gas 27 in the inner cylinder 19, the inner cylinder 19 is the outer cylinder 17
Enclosed to allow up and down movement. That is, when the inner cylinder 19 rises with respect to the outer cylinder 17, the piston rod 23 is relatively inserted into the inner cylinder 19.
The escape area of the oil 26 corresponding to the volume of the piston rod 23 inserted into the cylinder 9 is secured by compressing the gas 27, and when the inner cylinder 19 descends with respect to the outer cylinder 17, the piston rod 23 relatively moves to the inner cylinder. Although it is separated from 19, this inner cylinder 1
The gas 27 is enclosed in the inner cylinder 19 in order to allow the volume of the oil 26 of the piston rod 23, which is separated from 9, to flow from the escape area as the gas 27 expands. An insertion hole 23 a is formed in the piston rod 23 along the axis of the rod 23. The first liquid chamber 31 is formed between the lower surface of the upper wall 17a of the outer cylinder 17 and the top surface of the first piston 21, and the upper portion of the first liquid chamber 31 has a gas 30 such as nitrogen gas.
And an accumulator 28 in which the same oil 29 as the oil 29 in the first liquid chamber 31 is sealed is connected to the lower part. In addition, the upper wall 17a of the outer cylinder 17 has oil in the first liquid chamber 31.
A supply / discharge port 17b for supplying / discharging 9 is formed.

The inner cylinder 19 is divided by the second piston 22 into an upper second liquid chamber 32 and a lower third liquid chamber 33, and the side surface of the piston rod 23 is located close to the second piston 22. Orifice 2 that connects the second liquid chamber 32 and the third liquid chamber 33
3b is formed. A recess 21a is formed on the top surface of the first piston 21, and the valve body 34 is slidably inserted into the recess 21a. The upper end of a valve body rod 36 is connected to the center of the lower surface of the valve body 34.
3a is slidably inserted. The valve body rod 36 is configured to open and close the orifice 23b by sliding in the insertion hole 23a as well as sliding in the recess 21a of the valve body 34. A first compression coil spring 41, which is an elastic body of the present invention, is interposed between the valve body 34 and the bottom surface of the recess 21a. The spring 41 urges the valve element 34 in a direction away from the bottom surface of the recess 21 a, and the oil 29 supplied to the first liquid chamber 31.
The elastic force is smaller than the pushing down force of the valve element 34 due to the pressure. Reference numeral 42 in FIGS. 1 and 2 is a second compression coil spring interposed between the first piston 21 and the stepped portion 17c formed inside the outer cylinder 17, and this spring 42 is the first piston. 21 is pushed upward. That is, when the pressure of the oil 29 in the first liquid chamber 31 becomes small, the second compression coil spring 42 pushes the first piston 21 upward so that the first piston 21 moves to the inner end surface of the outer cylinder 17. The first compression coil spring 41 pushes up the valve element 34 so that the orifice 23b is opened and the second and third liquid chambers 32 and 33 communicate with each other. As a result, the shock absorber 14 serves to damp the vibration.

The liquid supply / discharge means 24 is a hydraulic pump 37 for supplying / discharging oil 29 to / from a power steering gear (not shown),
Pipe line 3 connecting the hydraulic pump 37 and the first liquid chamber 31
8 and a switching valve 39 provided at the same position. The power steering gear is housed in a gear box 43, and the lower end of a steering shaft 46 having a steering wheel 44 fixed to the upper end is inserted into the gear box 43. The discharge port 37 of the hydraulic pump 37 is a feed pipe 48.
Connected to the gear box 43 via the hydraulic pump 37
The intake port 37b of is connected to the gear box 43 via a return pipe 49. Although not shown, the return pipe 49 is provided with an oil tank for storing the oil 29.

The switching valve 39 is a three-port three-position switching solenoid valve, and has a case 39c in which a single first slide chamber 39a is formed in the center and a pair of second slide chambers 39b, 39b is formed at both ends. A valve body 39d slidably inserted into the first slide chamber 39a, a pair of valve rods 39e and 39e each having one end connected to both ends of the valve body 39d, and rods 39e for these valves.
A pair of third pistons 39f, 39f slidably inserted in the pair of second slide chambers 39b, 39b respectively connected to the other end of 39e, and a pair of first slide chamber 39a and a pair of third pistons 39a in the case 39c. Second slide chamber 39
b, 39b and a pair of coils 3 respectively provided between
9g and 39g.

The pair of second slide chambers 39b, 39b have a pair of third compression coil springs 39 having the same spring characteristic.
h, 39h are housed therein, and these springs 39h, 39h serve as third pistons 39f, 39f and valve rod 39.
The valve body 39d is urged to be positioned at the center of the first slide chamber 39a via e and 39e. Case 3
9c has a first port 39i communicating with the vicinity of the right end of the first slide chamber 39a, a second port 39j communicating with the vicinity of the left end of the first slide chamber 39a, and a third port communicating with the center of the first slide chamber 39a. 39k are formed. The pipe line 38 connecting the hydraulic pump 37 and the first liquid chamber 31 is a first pipe connecting the first port 39 i and the feed pipe 48.
Pipe line 38a, second port 39j and return pipe 49
And a third port 39k and a third pipe line 38c that connects the supply / discharge port 17b of the outer cylinder 17 to each other.

The pair of coils 39g, 39g are electrically connected to a battery 52 via a vehicle height changeover switch 51 provided in a driver's seat (not shown). This switch 51 is a normally open switch for three-position switching of manual operation and automatic return, and the switching contact b of this switch 51 has a coil 39 on the left side.
is electrically connected to g, and the switching contact c is the coil 39 on the right side.
electrically connected to g and the common contact a is connected to the battery 52. When this switch 51 is connected to the switching contact b, a current flows through the coil 39g on the left side, and a suction force to the left acts on the valve rod 39e on the left side.
d is moved to the left end of the first slide chamber 39a to connect the first port 39i and the third port 39k. When the switch 51 is connected to the switching contact c, a current flows through the coil 39g on the right side and the rod 3 for the valve on the right side.
The rightward suction force acts on 9e, and the valve main body 39d becomes the first
It is configured to move to the right end of the slide chamber 39a to connect the second port 39j and the third port 39k.

In this embodiment, the route bus is used as the vehicle, but this is an example, and a sightseeing bus or other vehicles may be used. Further, the axle may be an axle for rear wheels instead of an axle for front wheels. Further, in this embodiment, one end of the outer cylinder is pivotally attached to the chassis frame, and one end of the inner cylinder is pivotally attached to the axle, but not limited to this, one end of the outer cylinder is pivotally attached to the axle, and One end may be pivotally attached to the chassis frame. Further, in this embodiment, oil is supplied or sealed in the first to third liquid chambers, but liquids other than oil may be used. Furthermore, in this embodiment, a piston rod can be inserted into or removed from the inner cylinder by enclosing a small amount of gas such as nitrogen gas in addition to oil in the inner cylinder. Meet,
An accumulator in which oil and gas are sealed may be connected to the inner cylinder.

The operation of the vehicle height adjusting device thus constructed will be described. Normally, a route bus (not shown) is a flat paved road with the first piston 21 of the shock absorber 14 in contact with the inner end surface of the outer cylinder 17 (FIG. 1), that is, with the vehicle height lowered. Therefore, when a passenger (not shown) gets on and off at a stop and a passenger (not shown) gets on and off, the height from the road surface to the step (not shown) is relatively low, which facilitates getting on and off. Further, at this time, the valve body 34 is in the most raised position by the elastic force of the first compression coil spring 41 together with the valve body rod 36. As a result, since the orifice 23b is opened, the oil 26 in the inner cylinder 19 has a small orifice 23b.
Passing through b serves as resistance against vertical movement of the second piston 22 relative to the inner cylinder 19, so that vibration of the leaf spring 13 can be suppressed.

When a route bus approaches a bad road such as a railroad crossing or a steep slope, a driver (not shown) connects the vehicle height changeover switch 51 to the changeover contact b (FIG. 2). This switch 5
By the operation of 1, electric current flows through the coil 39g on the left side of the switching valve 39, and the valve body 39d moves to the first slide chamber 39a.
To the left end (FIG. 2), and the first port 39i and the third port 39k communicate with each other. Discharge port 37a of hydraulic pump 37
The oil 29 discharged from the feed pipe 48, the first conduit 38a, the first port 39i, the first slide chamber 39a, the third port 39k, the third conduit 38c, and the supply / discharge port 17b.
And is supplied to the first liquid chamber 31 through. The oil 29 supplied to the first liquid chamber 31 first causes the valve body 34 to move to the first compression coil spring 4
By pushing down against the elastic force of 1, the valve rod rod 36 is pushed down to close the orifice 23b (FIG. 2).
When the oil 29 is further supplied to the first liquid chamber 31, the first piston 21 descends with respect to the outer cylinder 17, and the distance between the shaft 16 at the upper end and the shaft 18 at the lower end of the shock absorber 14 increases (see FIG. 2). As a result, the vehicle height increases, and the bus can smoothly travel on rough roads such as railroad crossings and steep slopes.

Further, since the vehicle height changeover switch 51 is automatically separated from the changeover contact b when the hand is released, the first liquid chamber 31 is only provided while the driver is connecting the switch 51 to the changeover contact b.
The oil 29 is supplied to the vehicle and the vehicle height can be adjusted to a desired value. When lowering the vehicle height, the switch 51 may be connected to the switching contact c. At this time, the coil 39 on the right side of the switching valve 39
The electric current flows through g, and the valve body 39d moves to the first slide chamber 3
Since the oil 29 in the first liquid chamber 31 moves to the right end of 9a, the oil 29 in the first liquid chamber 31 is supplied to and discharged from the port 17b, the third conduit 38c, the third port 39k,
First slide chamber 39a, second port 39j, second conduit 3
8b, return to the return pipe 49, the first liquid chamber 31
The internal pressure decreases and rises due to the elastic force of the second compression coil spring 42, and the first piston 21 contacts the inner end surface of the outer cylinder 17. Further, since the pressure in the first liquid chamber 31 becomes small, the valve body 34 moves up together with the valve body rod 36 by the elastic force of the first compression coil spring 41, and the orifice 23b.
Is released. When the vehicle height is further increased, the valve body rod 36 closes the orifice 23b, so that the second piston 22 does not move relative to the inner cylinder 19, but
Instead, the gas 27 in the accumulator 28 repeats compression and expansion, whereby the first piston 21 moves relative to the outer cylinder 17, so that the shock absorber 1
4 has some buffering function.

4 and 5 show a second embodiment of the present invention. 4 and 5, the same reference numerals as those in FIG. 1 indicate the same parts. In this embodiment, the shock absorber 7
The first piston fixing means 71 for fixing the first piston 81 to the outer cylinder 17 in a state where the first piston 81 of No. 4 is in contact with the inner end surface of the outer cylinder 17 is attached to the outer peripheral surface of the outer cylinder 17,
A pair of first piston position sensors 91 a and 91 b for detecting the position of the piston 81 are attached to the outer peripheral surface of the outer cylinder 17. The first piston fixing means 71 is built in the case 71a, which is attached to the outer peripheral surface of the outer cylinder 17, a plunger 71b which is exposed from the case 71a into the outer cylinder 17 and is retractable from the case 71a. A fourth compression coil spring (not shown) that urges the plunger 71b in a direction projecting from the case 71a, and a plunger 71b that is built into the case 71a and resists the elastic force of the fourth compression coil spring when energized. And a coil (not shown) that draws in the. A ring-shaped concave groove 81b into which the plunger 71b can be inserted when the first piston 81 contacts the inner end surface of the outer cylinder 17 is formed on the outer peripheral surface of the first piston 81.

A pair of first piston position sensors 91a, 9a
One sensor 91a of 1b is attached to the outer peripheral surface near the upper end of the outer cylinder 17, and the other sensor 91b is mounted on the outer cylinder 17
Of the outer peripheral surface of the one sensor 91a is attached below the one sensor 91a by a predetermined distance. These sensors 91a, 91
Reference numeral b is a magnetic proximity switch using a reed switch, a Hall element / magnetic resistance element, a magnetic coil or the like as a detection element. In addition, the outer circumference of the first piston 81 has a first
When the piston 81 comes into contact with the inner end surface of the outer cylinder 17, a ring-shaped magnet 72 is embedded so as to face one of the sensors 91a, and the magnet 72 has the first piston 81 lowered to the outer cylinder 17 most. Sometimes the other sensor 91b
Are configured to face each other. The first piston 81 and the outer cylinder 17 are formed of a non-magnetic metal material such as austenitic stainless steel so as not to be magnetized by the magnet 72. Further, a vehicle height up lamp 76 and a vehicle height down lamp 77 are provided in the driver's seat (not shown).

A pair of first piston position sensors 91a, 9
1b and the switching contacts b and c of the vehicle height changeover switch 51 are connected to the control input of the controller 78,
The control output is connected to the coil of the first piston fixing means 71, the vehicle height up ramp 76, the vehicle height down ramp 77, and the pair of coils 39g, 39g of the switching valve 39, respectively. The configuration other than the above is the same as that of the first embodiment. In this embodiment, a magnetic proximity switch is used as the first piston position sensor, but a high frequency proximity switch, a capacitive proximity switch, or another position detection sensor may be used.

The operation of the vehicle height adjusting device of the vehicle thus configured will be described. When the route bus (not shown) is traveling at a low vehicle height, the first piston 81 causes the outer cylinder 1 to move.
Since the magnet 72 is in contact with the inner end face of the first piston 7 (FIG. 4) and the magnet 72 faces the first piston position sensor 91a (FIG. 4), the controller 78 fixes the first piston based on the detection output of the sensor 91a. Deactivate the means 71.
As a result, the plunger 71b projects from the case 71a due to the elastic force of the fourth compression coil spring, and the first piston 81
Since the first piston 81 is inserted into the concave groove 81b of the outer cylinder 17, the first piston 81 can be reliably fixed in a state of being in contact with the inner end surface of the outer cylinder 17. Further, the controller 78 turns on the vehicle height down lamp 77 based on the detection output of the sensor 91a.

When a route bus approaches a bad road such as a railroad crossing or a steep slope, the driver (not shown) connects the vehicle height changeover switch 51 to the changeover contact b (FIG. 5) and immediately releases the hand. .
The controller 78 detects that the switch 51 has once been connected to the switching contact b, and first applies a current to the coil (not shown) of the first piston fixing means 71 to cause the plunger 7 to move.
1b is pulled into the case 71a. As a result, the plunger 71b is disengaged from the concave groove 81b of the first piston 81, and the first piston 81 becomes slidable with respect to the outer cylinder 17. Next, the controller 78 controls the coil 3 on the left side of the switching valve 39.
Apply current to 9g. As a result, the valve body 39d becomes the first
By moving to the left end of the slide chamber 39a (FIG. 5), the first port 39i and the third port 39k communicate with each other, and the hydraulic pump 37
The oil 29 discharged from the discharge port 37a of the above is supplied to the first liquid chamber 31, and this oil 29 pushes down the valve body 34 and the orifice 2
After closing 3b, the first piston 81 is lowered with respect to the outer cylinder 17.

At this time, the magnet 72 separates from the one first piston position sensor 91a, so that the controller 7
8 turns off the vehicle height down lamp 77 based on this detection output. When the first piston 81 is farthest from the inner end surface of the outer cylinder 17, the magnet 72 faces the other first piston position sensor 91b (FIG. 5), so the controller 78
Turns on the vehicle height up lamp 76 based on the detection output of the sensor 91b, and stops the energization of the coil 39g on the left side of the switching valve 39 to stop the supply of the oil 29 to the first liquid chamber 31. Further, when lowering the vehicle height, the vehicle height changeover switch 51 may be connected to the changeover contact c. In this way, the driver instantaneously switches the changeover switch 51 to the changeover contact b or c.
The vehicle height can be increased or decreased to a predetermined height simply by connecting to the vehicle. Further, the driver can confirm whether the vehicle height of the bus is high or low just by visually recognizing the lighting of the vehicle height up lamp 76 or the vehicle height down lamp 77. The operation other than the above is substantially the same as that of the first embodiment, and thus the repeated description is omitted.

[0027]

As described above, according to the present invention, one end of the outer cylinder is pivotally attached to the chassis frame or the axle, one end of the inner cylinder is pivotally attached to the axle or the chassis frame, and the other end of the inner cylinder is attached. Is inserted into the outer cylinder and the first liquid is sealed inside, the first and second pistons connected by the piston rod having the insertion hole are inserted into the outer cylinder and the inner cylinder, and the second and the second cylinders inside the inner cylinder are inserted. An orifice that connects the three liquid chambers is formed in the piston rod, and the first
The rod for valve body integrated with the valve body inserted in the recess of the top surface of the piston is inserted into the insertion hole so that the orifice can be opened and closed, and the elastic body urges the valve body away from the bottom of the recess. Since the liquid supply / drainage means supplies / discharges the second liquid to / from the first liquid chamber of the outer cylinder by switching the vehicle height changeover switch, the vehicle height is lowered when traveling on a flat paved road. It is possible to improve the boarding / alighting property, and by passing the first liquid in the inner cylinder through the opened orifice, the shock absorber can be provided with the vibration damping function of the leaf spring, which is the original function of the shock absorber.

When the vehicle is traveling on a rough road, the second liquid is supplied to the first liquid chamber by the liquid supply / discharge means by switching the vehicle height changeover switch, and the supplied second liquid serves as the valve body. The orifice is closed by the valve body rod by pushing down against the elastic force of the elastic body, and the first piston is further lowered with respect to the outer cylinder. As a result, the vehicle height can be quickly increased with a simple operation, and the vehicle can smoothly travel on a rough road. The second liquid supplied to and discharged from the first liquid chamber is oil,
The liquid supplying / discharging means has a hydraulic pump for supplying / discharging the second liquid to / from the power steering gear, and a switching valve provided in a pipe line connecting the hydraulic pump and the first liquid chamber, and switches the vehicle height switching switch. Switch the switching valve by
If the second liquid is supplied to and discharged from the liquid chamber, the existing hydraulic pump for power steering can be used as the liquid supply / discharge means, and thus the number of parts and the number of assembling steps can be slightly increased.

Since the vehicle height is adjusted by moving the other end of the leaf spring up and down, the vehicle height can be adjusted only about half the vertical movement distance of the other end of the leaf spring. In the present invention, the vehicle height is increased by the amount that the first piston is separated from the inner end surface of the outer cylinder as compared with the spring type suspension, so that the vehicle height can be adjusted efficiently. Also, by improving the conventional leaf spring suspension with vehicle height adjustment function and lengthening one arm of the crank arm, the leaf spring tilts backward at a relatively large angle when the vehicle height is increased, There was a risk that the original function of
In the present invention, the function of the leaf spring is hardly impaired.

Further, the vehicle height adjusting device of the present invention detects the position of the first piston and the first piston fixing means for fixing the first piston to the outer cylinder when the first piston comes into contact with the inner end surface of the outer cylinder. If the first piston position sensor and the controller that controls the first piston fixing means based on the detection outputs of the first piston sensor and the vehicle height changeover switch are provided, the first piston position sensor is the outer cylinder of the first piston. When it is detected that the inner end surface of the piston is abutted, the controller operates the first piston fixing means based on the detection output of this sensor to fix the first piston to the outer cylinder. As a result, the state where the vehicle height is lowered can be reliably maintained. Furthermore, if an accumulator is connected to the first liquid chamber,
The gas in the accumulator repeats compression and expansion, whereby the first piston moves relative to the outer cylinder. As a result, the shock absorber functions as a shock absorber even when the orifice is closed.

[Brief description of drawings]

FIG. 1 is a sectional configuration diagram showing a state in which a vehicle height is lowered by a vehicle height adjusting device according to a first embodiment of the present invention.

FIG. 2 is a sectional configuration diagram corresponding to FIG. 1, showing a state where the vehicle height is increased by the vehicle height adjusting device.

FIG. 3 is a sectional view of an essential part of a vehicle including the vehicle height adjusting device.

FIG. 4 is a sectional configuration diagram corresponding to FIG. 1 showing a second embodiment of the present invention.

FIG. 5 is a sectional configuration diagram corresponding to FIG. 4, showing a state where the vehicle height is increased by the vehicle height adjusting device.

[Explanation of symbols]

11 axles 12 chassis frame 13 Leaf spring 14,74 Shock absorber 17 outer cylinder 19 inner cylinder 21,81 1st piston 21a recess 22 Second piston 23 Piston rod 23a insertion hole 23b Orifice 24 Liquid supply / drainage means 26 oil (first liquid) 28 Accumulator 29 oil (second liquid) 31 First liquid chamber 32 Second liquid chamber 33 Third liquid chamber 34 Disc 36 Valve body rod 37 hydraulic pump 38 pipelines 39 Switching valve 41 First compression coil spring (elastic body) 51 Height switch 71 First Piston Fixing Means 78 Controller 91a, 91b First piston position sensor

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Claims (4)

(57) [Claims] 1. A leaf spring (13) interposed between an axle (11) and a chassis frame (12) for suspending the chassis frame (12), the axle (11) and the chassis frame (12).
In a vehicle equipped with a shock absorber (14) interposed between the shock absorber (14) and the leaf spring (13) for suppressing vibration of the leaf spring (13), the shock absorber (14) has one end on the chassis frame (12) or the axle (11). An outer cylinder (17) pivotally attached, one end pivotally attached to the axle (11) or the chassis frame (12) and the other end slidably inserted into the outer cylinder (17) and the first liquid ( 26) and an inner cylinder (19), and a first piston (21, 21, slidably inserted into the outer cylinder (17).
81) and a second piston (22) slidably inserted in the inner cylinder (19).
A piston rod (23) that connects the first piston (21, 81) and the second piston (22) and has an insertion hole (23a) formed along the axis, and the outer cylinder (17) Liquid supply / discharge means (24) capable of supplying / discharging the second liquid (29) to / from the first liquid chamber (31) formed between the inner end surface and the top surface of the first piston (21, 81), The second pistons (2) are formed in the inner cylinders (19), respectively.
2) second and third liquid chambers (32, 33) partitioned into one end side and the other end side of the inner cylinder (19), respectively, and the second piston (22) on the side surface of the piston rod (23). )
And the second and third liquid chambers (32, 33) formed close to
An orifice (23b) that communicates with the recess (21a) formed on the top surface of the first piston (21, 81).
A valve body (34) slidably inserted into the valve body (34), and the insertion hole (23a) formed integrally with the valve body (34) as the valve body (34) slides in the recess (21a). ) A valve body rod (36) capable of opening and closing the orifice (23b) by sliding inside, and the valve body (34) interposed between the valve body (34) and the bottom surface of the recess (21a). Elasticity smaller than the pressing force of the valve body (34) due to the pressure of the second liquid (29) supplied to the first liquid chamber (31), which urges the (34) in a direction away from the bottom surface of the recess (21a). A vehicle height changeover switch (51) provided with an elastic body (41) having a force and for changing the vehicle height by the driver is provided in the driver's seat, and by changing the vehicle height changeover switch (51), The second liquid (2) is supplied to the first liquid chamber (31) through the liquid supplying / discharging means (24).
9) A vehicle height adjusting device configured to supply and discharge the vehicle. 2. A second liquid (29) supplied to and discharged from the first liquid chamber (31)
Is oil, and the liquid supply / discharge means (24) is connected to the power steering gear by the second
The hydraulic pump (37) for supplying and discharging liquid (29) and this hydraulic pump (3
7) and a switching valve (39) provided in a pipe line (38) connecting the first liquid chamber (31), and the switching valve (39) is provided by switching a vehicle height switching switch (51). To the second liquid (2) in the first liquid chamber (31).
9. The vehicle height adjusting device for a vehicle according to claim 1, wherein 9) is supplied and discharged. 3. A first piston fixing means (71) for fixing the first piston (81) to the outer cylinder (17) when the first piston (81) contacts the inner end surface of the outer cylinder (17). ), A first piston position sensor (91a, 91b) for detecting the position of the first piston (81), and detection outputs of the first piston sensor (91a, 91b) and the vehicle height changeover switch (51). A controller (78) for controlling the first piston fixing means (71) based on the above.
Alternatively, the vehicle height adjusting device according to item 2. 4. The vehicle height adjusting device for a vehicle according to claim 1, wherein an accumulator (28) is connected to the first liquid chamber (31).